1. Field of the Invention
The present invention relates to a car navigation display system that displays additional information on a monitor screen on which audio or video information from a music CD or video DVD is being displayed by a car navigation system.
2. Description of the Prior Art
An early car navigation system displays only map information (a map and associated characters or the like) on the monitor screen at the time of playing back a map disk. Since a CD and a DVD are now in widespread use as AV (music and video) media, however, the current car navigation system is additionally equipped with a playback capability that shuffles one CD/DVD drive back and forth between a map disk and an AV disk such as a music CD or video DVD. With such a system, for example, when the music CD is being played back, track information of the CD being played back is displayed on the monitor screen as depicted in FIG. 4 and music is reproduced from a loudspeaker. When the video DVD is being played back, such reproduced pictures as shown in FIG. 5 is displayed on the monitor screen, and the audio of its contents are output from the loudspeaker.
With the conventional car navigation display system of the above construction, when the AV disk is being played back, the monitor displays only information about the AV media without displaying any navigation information. Hence, when driving while playing back the AV disk, the driver cannot get any traffic congestion or map information. In particular, during playback of the music CD, since the monitor screen merely displays the track information being played back, the display changes only slightly and no useful information is not offered to the driver.
Further, there is also under study a system that permits simultaneous use of the navigation function by the map disk and the AV disk playback function, but to playback the map and AV disks at the same time, it is necessary to mount a player for the map disk and an AV disk player on the navigation system unit. This inevitably makes the unit bulky, which is undesirable due to limitations of space in the car, and such an integral structure raises the cost of the system. Under the present circumstances, it is customary in the art to employ a dual-purpose player for reading out the map disk and playing back the AV disk.
It is therefore an object of the present invention to provide a navigation display system that enables navigation information or the like to be displayed on the monitor screen on which pictures are being played back from the AV disk.
According to an aspect of the present invention, in a car navigation display system provided with a CD/DVD drive which shuffles back and forth between a map disk and an AV disk, when a map disk is played back, map data such as destination route is prestored in an internal memory or external recording medium, then at the time of playing back the AV disk, the prestored map data is read out of the internal memory or external recording medium, and the read-out map data is displayed as a slave picture, or in one of two divided monitor screen areas, together with reproduced pictures of the AV disk on the monitor.
According to another aspect of the present invention, in a car navigation display system provided with a CD/DVD drive which shuffles back and forth between a map disk and an AV disk, when a map disk is played back, traffic information fed from VICS, beacon receivers, or the like is stored in an internal memory or external recording medium, then at the time of playing back the AV disk, the stored traffic information is read out of the internal memory or external recording medium, and the read-out traffic information is displayed as a slave picture, or in one of two divided monitor screen areas, or as a telop, together with the reproduced pictures of the AV disk on the monitor.
According to still another aspect of the present invention, in a car navigation display system provided with a CD/DVD drive which shuffles back and forth between a map disk and an AV disk, information received from information equipment connected to the outside is stored in an internal memory or external recording medium, then at the time of playing back the map disk or AV disk, character/image data contained in the stored information is read out therefrom, and the character/image data thus read out is displayed as a slave picture, or in one of two divided monitor screen areas, or as a telop, together with the reproduced pictures of the map disk or AV disk on the monitor.